Ovulation Calculator
When did your last period start?
E.g. 18/01/2020
Usually, how long is your cycle?
Cycles typically vary from 23 to 35 days
Estimate your ovulation day
likelihood of ovulating today
Due to your cycle length, unfortunately we can't estimate an ovulation probability. We recommend that you use a Digital Ovulation Test to accurately detect your most fertile days.
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Start of your last period
  20%
Likelihood of ovulating on this date
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In partnership with Clearblue®.
Results are based on the information you have provided and data from the publication below: Sarah Johnson, Lorrae Marriott & Michael Zinaman (2018): “Can apps and calendar methods predict ovulation with accuracy?”, Current Medical Research and Opinion, DOI:10.1080/03007995.2018.1475348

Disclaimer: The information provided by this calculator is not a diagnosis. The calculations that are provided are an estimate based on averages and that the calculations by the patients’ health care provider is the best date to use. This site is not responsible for incorrect usage of this calculator or incorrect booking times based on information provided by this calculator.